The breast is a specialized, glandular structure including a system of complicated breast ducts that radiate from the nipple and that are bound together by fairly dense connective tissue. Each of these breast ducts includes an associated ductal orifice on the surface of a nipple through which ductal fluid may be expressed. Each duct includes a series of successive interlobular branches that drain through the main, lactiferous branch, which terminates and exits the breast at the nipple via the associated ductal orifice. Immediately proximate the ductal orifice, each lactiferous duct includes a lactiferous sinus in which ductal fluid may accumulate. A ductal sphincter resides within the lactiferous sinus and prevents ductal fluid from unintentionally exiting the breast duct through its associated ductal orifice.
Breast cancer is believed to begin in the lining of these breast ducts. For several decades significant members of the medical community dedicated to studying breast cancer have believed and shown that the cytological analysis of cells retrieved from nipple discharge fluid from within breast ducts may provide valuable information leading to identifying patients at risk for breast cancer. Indeed, Papanicolaou contributed to the genesis of such a possibility of a “Pap” smear for breast cancer by analyzing the cells contained in nipple discharge. More recently, cancer specific markers have been detected in ductal fluid obtained by nipple aspiration. However, the retrieval techniques and instruments used by these members of the medical community did not routinely obtain meaningful ductal fluid samples.
In their attempts to retrieve the breast duct fluid sample including ductal epithelial cells, practitioners introduced wash fluids into a breast duct using indwelling hair-like single lumen catheters. After the fluid was introduced into the duct, the fluid introduction catheters were removed. Then, externally applied nipple aspiration techniques or external pressure applied to the breast were used to collect samples of the ductal fluid. However, these techniques required that significant, sometimes painful, pressure be created on the nipple surface or along the sides of the breast to overcome the fluid retaining properties of the ductal sphincter. Also, these techniques did not routinely provide meaningful ductal fluid samples with a sufficient number of ductal epithelial cells for a meaningful cellular analysis. These techniques typically caused the recovery of samples with twenty or fewer ductal epithelial cells. Additionally, these techniques did not provide samples with cell clusters of 10 or more cells. As a result, the obtained fluid samples could not consistently provide an accurate indication of whether or not the duct from which they were retrieved included precancerous or cancerous cells. Consistent, meaningful ductal epithelial cell samples have been provided by the medical instrument disclosed in U.S. Pat. No. 6,413,228 to Hung et al. that is hereby incorporated by reference in its entirety.
Other medical instruments, such as those used during galactography, are introduced into the breast duct in order to visually determine the presence of cancerous cells within a breast duct. However, these devices typically extend a significant distance out of the breast duct during the performed procedure. These distances may be twelve inches or greater. As a result, when an operator is not holding the tool, the moment created by the weight and length of the section of the instrument extending out of the duct may cause the indwelling portion of the instrument to engage the sidewalls of the duct, torque and/or kink the duct and distort the nipple. These effects on the duct and nipple may impede the procedure by twisting or crimping the indwelling portion of the instrument, possibly injuring the patient's duct and causing significant discomfort to the patient. As a result, a patient must either endure the pain and discomfort caused by these long instruments or an attendant must constantly support the instrument above the patient during the medical procedure. However, in the confined space around an operating table and in the area surrounding a nipple surface, it is not practical to have an attendant constantly holding the end of the instrument that is extending into the breast duct. Therefore, prior to receiving the procedure, a patient must decide to either experience discomfort during the procedure or choose not to have the procedure performed. Prior art instruments are also not ergonomically designed for easy grasping and adjusting by a practitioner or attendant while acting in the area surrounding a nipple.